Vacuum pumps may be fitted to road vehicles with gasoline or diesel engines. Typically, the vacuum pump is driven by a camshaft of the engine, an electric motor or a belt drive. Rotating vane vacuum pumps typically comprise a housing defining a cavity having an inlet and an outlet and a drivable vane member for rotary driven movement inside the cavity. The housing may include a cover which closes the cavity. The drivable vane member is typically movable to draw fluid into the cavity through the inlet and out of the cavity through the outlet so as to induce a reduction in pressure at the inlet. The inlet is connectable to a consumer such as a break booster or the like.
In most vacuum pumps which are of the vane pump type, the rotor is driven and comprises a radially arranged slot in which the vane may freely slide and the vane is further guided by the cavity walls. A comparable vane pump is for example disclosed in EP 2 024 641. Such vane pumps are also called mono vane pumps since they incorporate one single vane which is slidable in a radial direction of rotor.
Further, vacuum pumps having multiple vanes which are separately guided and supported on a supporting surface are also know, as for example shown in DE 40 20 087. Such vacuum pumps have the disadvantage that they incorporate multiple individual parts and multiple friction surfaces which makes it difficult to seal them against the environment to effectively induce a vacuum inside the cavity.
From the WO 2009/052929 a vacuum pump is known comprising a housing defining a cavity having an inlet and an outlet, a drivable vane member for a rotary driven movement inside the cavity and a rotor inside the cavity. The vane is arranged in a radial slot of the rotor. Further the vacuum pump comprises an excenter shaft with a stroke pin which is coupled to the vane. The rotary axis of the excenter shaft is offset from the rotary axis of the rotor and the rotary axis of the stroke pin is offset from the rotary axis of the excenter shaft. The vane is guided by means of the excenter shaft and the stroke pin. In general the movement principal of such a vacuum pump is comparable to the principle of rotary piston pumps, as for example described in GB 338,546.